Device for selecting mailpieces

ABSTRACT

A mailpiece selector device for separating mailpieces one-by-one from a stack of mailpieces and for transporting them downstream, the device comprising at least a first guide co-operating with a plurality of opposite selector rollers to select said mailpieces one-by-one and to transport them downstream, said first guide being comb-shaped and able to pivot about a first pivot axis in opposition to first resilient return means, one end of at least one tooth of the comb being coated with a wear-resistant material.

TECHNICAL FIELD

The present invention relates to the field of mail handling, and it relates more particularly to a device for selecting mailpieces that is implemented in an automatic feed module or “feeder” of a franking machine or “postage meter” for franking mailpieces.

PRIOR ART

Conventionally, a franking machine must be adapted to receive various types of mailpiece, such as documents, letters, or envelopes of greater or lesser thickness, typically lying in the range 0.1 millimeters (mm) to 16 mm. To this end, on the upstream side, it often includes an automatic feed module making it possible, in particular, to convey said mailpieces at various speeds. That automatic feed module usually includes means for receiving/stacking, selecting, transporting, and possibly closing said mailpieces.

European Patent EP 0 856 483, granted to the Applicant, shows an example of such an automatic feeder including a selector module adapted to passing mailpieces of various thicknesses, however the selection quality of that module is highly dependent on the force applied by the single guide to the mailpiece. For mailpieces of small thickness, typically of thickness less than 6 mm, that force must be large in order to limit the number of double passes, i.e. the number of times two envelopes pass through together towards the franking machine, whereas said force can be small for mailpieces of larger thickness. Such double passes are highly detrimental because they give rise not only to one of the two mailpieces being over-invoiced (because two mailpieces are weighed instead of one), but also to the upper mailpiece not being franked and to the lower mailpiece not being closed. Unfortunately, since the guide is pressed against the mailpiece by a compression spring in order to avoid such double passes, mailpieces of large thickness, and more particularly large-thickness mailpieces having windows, might be damaged or torn.

OBJECT AND DEFINITION OF THE INVENTION

An object of the present invention is to mitigate the drawbacks resulting from two envelopes passing through together by proposing a mailpiece selector device for a franking machine feeder that can limit such double passes to at the most 1 in 1000.

This object is achieved by a mailpiece selector device for separating mailpieces one-by-one from a stack of mailpieces and for transporting them downstream, wherein said mailpiece selector device comprises at least a first guide co-operating with a plurality of opposite selector rollers to select said mailpieces one-by-one and to transport them downstream, said first guide being comb-shaped and able to pivot about a first pivot axis in opposition to first resilient return means, wherein one end of at least one tooth of the comb being coated with a wear-resistant material.

By means of this specific structure and because of the absence of wear of the material, the use of a second guide becomes optional, and the quality of selection of thin envelopes is improved.

Preferably, said material is a ceramic or a carbide.

Advantageously, the mailpiece selector device may further comprise a second guide mounted to pivot about a second pivot axis in opposition to second resilient return means.

Depending on the embodiment, said second pivot axis and said first pivot axis may form a common pivot axis or said second pivot axis may be offset upstream relative to said first pivot axis.

Preferably said second guide is comb-shaped, an elastomer blade being fastened to each of the teeth of the comb.

The present invention also relates to a mailpiece feeder for a franking machine, which feeder includes an above-mentioned mailpiece selector device.

BRIEF DESCRIPTION OF THE DRAWING

Other characteristics and advantages of the present invention appear more clearly from the following description given by way of non-limiting indication and with reference to the accompanying drawing, in which:

FIG. 1 is a longitudinal section view of a mailpiece selector device of the invention; and

FIG. 2 is a plan view of the first guide of the selector device of FIG. 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

An automatic mailpiece feed module conventionally has a feed zone formed essentially by a deck designed to receive a stack of mailpieces and including first transport rollers for driving the mailpieces downstream (and against a referencing wall) at a separation zone having a separator device in which the mailpieces are extracted one by one from the stack of mailpieces. Second transport rollers are, in general, provided at the outlet of said separation zone for the purpose of conveying the mailpieces extracted in this way downstream. Such an automatic feeder is, for example, illustrated in the European patent cited in the introduction to the present application.

FIGS. 1 and 2 show, more precisely, a mailpiece separator device 10 of the invention, which device essentially comprises a first guide 12 followed by a second guide 14, both of which co-operate with a plurality of opposite selector rollers 16A, 16B, 16C to select a single mailpiece only and to transport it downstream.

In the example shown, the first and second guides are hinged about a common pivot axis 18, and each of them can pivot in opposition to resilient return means, e.g. compression springs 20A, 20B; 22, as the mailpieces pass over the selector rollers. Each of the two resilient return means is also in abutment against a portion of framework 24 of the selector device. Preferably, the second guide is further provided with an operating lever 26 for enabling an operator to act manually to clear the path for transporting the mailpieces, while mailpieces of large thickness are being processed, typically of thickness greater than 6 mm and less than 16 mm (conventionally the maximum threshold for selection for a feeder). Without this retraction possibility, the elastomer blade might wear more rapidly and damage the more fragile envelopes, such as envelopes having windows. In addition, such thick envelopes can be selected in entirely satisfactory manner by the first guide alone, without any risk of two of them passing through together.

It should be noted that, although, by way of example, reference is made to a compression spring, a traction spring could also be suitable subject to having a different configuration for fastening the spring to the framework.

It should also be noted that the manual operation for operating the second guide by means of the operating lever 26 can be replaced by automatic operation (not shown) subject to making provision for the two guides to move together, it being possible for this to be obtained by decoupling the two pivot axes of the two guides, the pivot axis of the second guide being offset upstream relative to the pivot axis of the first guide, and by making provision for the first guide to have at least one bearing surface designed to co-operate with at least one abutment on the second guide, so that, above a predetermined mailpiece thickness, movement of the first guide automatically causes the second guide to move progressively.

As is known, the first and second guides 12, 14 are not disposed perpendicularly to the transport path of the mailpieces, but rather they are inclined downstream by about 45°. Each of them is comb-shaped, with each of the teeth of the comb being disposed between two adjacent selector rollers. In the example shown, which has three selector rollers (not shown), the first guide has four teeth and the second guide only has two teeth.

In accordance with the invention, on the first guide 12, the end of at least one tooth, and preferably each of the ends of the two central teeth or of all four teeth is coated with a wear-resistant material, such as a ceramic or a carbide, forming a selection finger 12A, while on the second guide 14, each of the teeth is provided with an elastomer blade 14A. The elastomer blade has a has a very high coefficient of friction in order to guarantee the best possible contact with the mailpiece but it wears relatively quickly and might damage the more fragile mailpieces by creasing or jamming, whereas the ceramic finger does not wear while also limiting the risks of the mailpieces being scratched. The ceramic material forming each finger 12A of the first guide 12 is preferably a titanium oxide, such as Ti-Cord from the French supplier Saint-Gobain, deposited by heat transfer. This procures very high hardness for the ceramic finger which can be kept in place throughout the life of the feeder, and the roughness of the material is sufficient to grip the mailpieces firmly while also preventing any tearing as they go past.

The selector device of the invention operates as follows. Once the mailpieces to be processed have been placed on the deck of the feed device, then for mailpieces of small thickness, i.e. of thickness less than 2 mm, and for mailpieces of standard thickness, i.e. of thickness lying in the range 2 mm to 6 mm, most of the selection work is done by the first guide, the second guide, which remains subjected to its return spring 22, catching any double passes if necessary. Beyond this second threshold, i.e. for envelopes that are even thicker, for which the problem of double passes does not exist in practice, the second guide can be active or preferably non-active, thereby preventing said second guide, on which the return spring 22 acts, from being worn prematurely by repeated impacts with the mailpieces, and preventing the more fragile mailpieces, such as envelopes having windows, from being creased.

Thus, with the present invention, the roughness of the ceramic material makes it possible to select the mailpieces very effectively without scratching them, and the hardness of said material prevents premature wear thereof. Thus, for envelopes of small thickness, it is possible to refrain from using a second guide, e.g. by using an operating lever. The periods of unavailability of the feeder are thus reduced. 

1. A mailpiece selector device for separating mailpieces one-by-one from a stack of mailpieces and for transporting them downstream, wherein said mailpiece selector device comprises at least a first guide co-operating with a plurality of opposite selector rollers to select said mailpieces one-by-one and to transport them downstream, said first guide being comb-shaped and able to pivot about a first pivot axis in opposition to first resilient return means and said first guide being comb-shaped, wherein one end of at least one tooth of the comb being coated with a wear-resistant material.
 2. A mailpiece selector device according to claim 1, wherein said material is a ceramic or a carbide.
 3. A mailpiece selector device according to claim 1, further comprising a second guide mounted to pivot about a second pivot axis in opposition to second resilient return means.
 4. A mailpiece selector device according to claim 3, wherein said second pivot axis and said first pivot axis form a common pivot axis.
 5. A mailpiece selector device according to claim 3, wherein said second pivot axis is offset upstream relative to said first pivot axis.
 6. A mailpiece selector device according to claim 3, wherein said second guide is comb-shaped, an elastomer blade being fastened to each of the teeth of the comb.
 7. A mailpiece feeder for a franking machine, which feeder includes a mailpiece selector device according to claim
 1. 